Directions:

1. Preheat oven to 350°F. Spray two 8-inch round cake pans with cooking spray and line each with a parchment paper round.
2. Sift all the dry ingredients into a large bowl. In a separate bowl mix the sugar, eggs, oil, milk, water, yogurt and lemon extract. Add all of the wet ingredients to the dry and mix.
3. Separate the batter evenly into six bowls. Color each of the batters with the gel food colors. Red, orange (yellow + red), yellow, green (yellow + blue), blue, and violet (blue + red).
4. Bake the layers in the prepared pans one color at a time for 10-15 minutes or until the cake separates from the edges of the pan and a toothpick is dry once inserted into the center of the cake. Wash, dry and spray the cake pans between baking each layer.
5. Cool the cakes completely on cooling racks.
6. Trim the round tops off of each cake with a serrated knife.
7. Carefully stack all the layers of the cake with about ¼ cup of icing between each layer. Place a thin layer of buttercream icing around the whole cake and chill for at least 30 minutes. After the buttercream is set add a final layer of buttercream around the whole cake. Decorate with crumbs or sprinkles. Enjoy!